In general, the present invention relates to the field of control of electronic devices, and more particularly to a method and apparatus for activating a function of an electronic device.
Devices for inputting information and/or commands into electronic devices are well known. For example, handheld electronic devices such as personal digital assistants, pagers, and cellular telephones typically employ a series of keys or buttons for the operator to press in order to activate a function of the device or input information to the device. A disadvantage of this arrangement is in many instances the operator must be able to see (or at least feel) the buttons to determine which button should be pressed. Moreover, the operator must have the device in a proper handheld position so that the operator can manipulate the keys. In addition, some electronic devices have removable covers or a closable configuration in which the operator cannot access the desired keys without removing the cover or opening the device.
One example of an electronic device function to be activated is a backlight for illumination of the display and/or keys. If a separate button is added to activate the backlight, this incurs the disadvantage of an additional button that occupies valuable space on the device. The user must memorize the location of the button to be able to find it in a low-light environment. Other ways of activating a backlight, such as using a press-and-hold function of an existing key, can be difficult for the user to find and cumbersome to activate. One solution to this problem has been to activate a backlight whenever any keys are pressed. However, since the first button to be pressed is not lit when pressed, the operator runs the risk of pressing an undesirable button. Further, in situations where the backlight remains on for only a predetermined period of time after being activated, it is cumbersome for the user to find an appropriate button to restart the backlight sequence without activating an undesired function. Accordingly, there exists a need to conveniently activate a function or enter information into electronic devices.